1. Field of the Invention
This invention relates generally to air-to-air heat exchangers, and more particularly to air-to-air heat exchangers for use in animal confinement buildings.
2. Description of the Prior Art
Due to the drastic increase of energy costs over the past several years, there has been a renewed interest in air-to-air heat exchangers. In general, the air-to-air heat exchangers are designed to use the heat in the air that is exhausted from a building to warm or preheat fresh air as it is brought into the building.
A heat exchanger that is used in an animal confinement building is subjected to severe operating conditions. That is, the exhaust air in an animal confinement building contains a great deal of humidity, dirt and dust. It is important to be able to easily clean the warm (exhaust) air stream of the heat exchanger. The prior art units to date have not adequately addressed or solved this cleaning problem. Through a number of novel design configurations, the present application provides for a heat exchanger that allows easy cleaning.
In cold weather, the moisture condensing out of the air may freeze on the plates as it exits through the heat exchanger. As the ice builds up on the plates, the exhaust air flow becomes restricted. A number of prior art heat exchangers use a timer, wherein at preset intervals, the fan blowing in the intake air is shut off. This provides for only the exhausting of warm air, which melts any ice build-up. The major disadvantage of such an arrangement is that the heat exchanger is defrosted whether or not there is an ice build-up. The present invention provides for a demand defrosting, which assures that the unit will defrost only when necessary.
The present invention effectively addresses the problems of the prior art heat exchangers and provides for a highly efficient, and easily cleanable unit.